Can I use a British phone (not a mobile) in Spain?

Question

Are the connections/sockets the same? If not, are adaptors available?

Answer 1

Connectors not the same. No adaptors.
The nearest that you'll get would be a lead with a Spanish phone plug at one end and an RJ11 (the little 4 pin socket with a central clip) at the other. If your phone doesn't have an RJ11 socket in its base than that won't be any use.

There is no guarantee that the phone would work anyway as the local exchange dialling system may be incompatible.